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L E Panin

Publications and source records attributed to L E Panin.

157 records · Page 9Linked to original sources
PubMedDate not supplied

[The cooperative effect of hydrocortisone, adrenaline, and high density lipoproteins in regulating the activity of multiple forms of liver hexokinase].

High density lipoproteins (HDL) were shown to modulate the effect of hydrocortisone and adrenaline on activity of hexokinase in surviving liver tissue slices. The hormones inhibited the enzymatic activity while in presence of HDL the hormones exhibited an opposite effect. The phenomenon observed was termed a "cooperative effect"; it could not be reproduced by any single components of the system studied. Mechanism of the effect involved induction of all the multiple hexokinase forms which was abolished by actinomycin D. A specific function could be ascribed only to HDL3; HDL2, low and very low density lipoproteins did not exhibit any effects. The cooperative effect of HDL and of the adaptive hormones was also inhibited in the surviving liver tissue slices by vinblastine, gordox and methylamine thus demonstrating the sophisticated nature of the mechanism.

Animals↗
PubMedDate not supplied

[Changes in glycolysis and glycogenolysis in tissues and level of certain hormones in blood and urine from rats with varying lengths of cold adaptation].

The production phase changes of adaptive hormones and the activity of key glycolytic and glycogenolytic enzymes were studied in Wistar rats exposed to a long-term (1-49 day) cold (+5 degrees C) exposure. The allosteric mechanisms responsible for regulating carbohydrate metabolism were shown to interact with endocrine ones and to modulate their effects. In cold acclimation, activation of the sympathoadrenal system aimed not only at increasing carbohydrate metabolism, but at enhancing the metabolism of fats and calorigenic effects.

Adaptation, Physiological↗
PubMedDate not supplied

[Changes in the structure of erythrocyte membrane and Na+. K+-ATPase activity in participants of the Soviet-Canadian trans-Arctic ski pass].

Changes in the structure of erythrocyte membranes and kinetics of the membrane-bound enzyme Na+, K(+)-ATPase were measured in members of the Canadian-Soviet transarctic ski pass that took place in March-May 1988. Hemoglobin content decreased at the Pole (by 22%) and partially recovered in Canada; phospholipids in erythrocyte membranes diminished at the Pole and in Canada (by 30%). During the pass water concentrations in membrane proteins and phospholipids increased significantly. Changes were found in rheological properties of membranes, e.g., viscosity of erythrocyte shadow suspensions at critical temperature (Tc) which is within the physiological range (36-38 degrees C) and viscosity in the temperature range 34-42 degrees C. Electric conductivity varied as a function of temperature (delta sigma(T)]. At 36-38 degrees C sigma showed abnormal variations. The integral intensity of IR-spectra of absorption bands of COp (peptide bonds) and P-O-C (phospholipids) decreased and the half-width of the COp absorption band increased during the pass. The activity of Na+, K(+)-ATPase of erythrocyte shadows diminished which was in correlation with membrane structure changes. The temperature optimum of Na(+)-, K(+)-ATPase occurred at 37-38 degrees C and coincided with the region of the structural phase transition detected by the authors.

Adult↗
PubMedDate not supplied

[Cooperative effect of high density lipoproteins and adaptive hormones in chromatin activation in rat liver].

Fluorescent probing of rat liver chromatin with acridine orange (AO) and ethidium bromide was employed to investigate the rat liver chromatin activation under stress in vivo and in vitro. A significant increase of molar concentration of AO binding sites with chromatin in nuclei suspension was demonstrated after intensive physical exercises and partial hepatectomy. These results reveal chromatin activation under these stress conditions. For the first time the chromatin activation was shown to be a result of the cooperative effect of hydrocortisone and blood plasma high density lipoproteins (HDL). Both HDL2 and HDL3 contribute to this cooperative action. The increase of concentration of AO binding sites and simultaneous increase of the ratio of red to green fluorescence (alpha), which represents the amount of one-stranded nucleic acids, show that chromatin activation in this case is accompanied by the derepression of new genes and also by the enhanced expression of already functioning ones. Adrenaline did not change the amount of AO binding sites but increased index alpha. This evidences for the enhanced expression of already functioning genes. Hydrocortisone-dependent chromatin activation led to the increase of the binding constant of AO with DNA, while molar concentration of binding sites of the probe was practically unaltered. At the same time, cooperative effect of hydrocortisone and HDL did not alter the constants of AO binding, but the concentration of the probe binding sites with DNA was significantly increased.

Adaptation, Physiological↗
PubMedDate not supplied

[The mechanism of anti-insulin effect of apoprotein B].

The existence of common epitope in insulin molecule and apolipoprotein B one was shown by means of enzyme immunoassay. Similar epitopes were revealed in apoB-containing lipoproteins (VLDL and LDL) by dot-immunobinding and immunoelectroblotting. Epitopes locate on the surface of lipoproteins and are not screened by lipids. The existence of common epitopes is the reason of competition between insulin and LDL. The experiments with isolated perfused rat hindquarter demonstrate that insulin increased the glucose uptake by muscle and LDL decreased it. Simultaneous perfusion with LDL and insulin leads to reduced insulin action due to completion for insulin receptors. After the recovery of S-S bounds apoB forms some proteins, containing common epitopes with insulin. The presence of such proteins was shown in lipoprotein-free serum. Apoprotein B and its derivates seem to be insulin antagonists with marked antiinsulin action.

Animals↗
PubMedDate not supplied

[Tocopherol level and lipid peroxidation in Wistar rat tissues during adaptation to cold].

The content of lipid peroxidation (LPO) products and tocopherol was studied in the plasma, adrenals, brown fat, heart, thymus, liver tissue, microsomes and mitochondria of Wistar rats in various periods of cold acclimation (+4 degrees C during 2, 5, 24 hours and 5, 10, 15, and 49 days). Within the first 24 hours of cold exposure, there were periods of low levels of LPO products which, as their following elevation, did not coincide in time both for various tissues and for subcellular structures. The liver was used as an example to show that the activity of glutathione reductase and glutathione peroxidase enhanced. The rats' adaptation to moderately low temperatures occurred with the stabilized LPO processes and elevated body's tissue tocopherol levels: in the first hours of exposure by mobilizing its endogenous stores, on long-term exposure by enhancing its utilization from the diet.

Adaptation, Physiological↗
PubMedDate not supplied

[The role of the mononuclear phagocyte system in regulating protein biosynthesis in rat organs and tissues in ontogeny].

In experiments on Wistar rats, we demonstrate that activation of mononuclear phagocytes by a lipopolysaccharide (prodigiosin) results in a marked increase of protein biosynthesis in various organs and tissues. This control mechanism is most distinct in mature rats and undergoes involution in older rats. Cell elements in the mononuclear phagocytes (resident macrophages) originate from the bone marrow. Decrease in the reserve capacity of the bone marrow with age in response to prodigiosin administration suggests an important role of this mechanism during aging.

Aging↗
PubMedDate not supplied

[The effect of stimulants of the mononuclear phagocytosing system on protein synthesis in rat organs and tissues].

It has been demonstrated in rat experiments that stimulation of the mononuclear phagocytizing system with a polysaccharide intensifies protein biosynthesis in various organs and tissues. In administration of high-polymer RNA into the organism increase of protein synthesis was encountered only in immunocompetent and blood-forming tissues. It is concluded that a stimulating effect in relation to macrophages is characteristic of high-polymer compounds which are absorbed by them due to receptor mediated endocytosis. The differences in the receptor apparatus of the resident macrophages determine the discovered difference in the intensification of protein biosynthesis in the organs and tissues of rats.

Adjuvants, Immunologic↗
PubMedDate not supplied

[Change in histone proteins in rat liver chromatin during exposure of the animal to functional stress].

Pattern of rat liver histones at intensive physical exercises with preliminary injection of lysosomotropic drugs was studied by method of electrophoresis in PAAG. Elevation of the acetylated forms of histone H4 was revealed. The increased proteolysis of lysine-rich histones (H1, H2A, H2B) was shown in swimming rats previously stimulated by prodigiosan. The possible role of lysosomal proteinases of liver cells in mechanism of chromatine activation is discussed.

Animals↗
PubMedDate not supplied

[The effect of extracorporeal thermal-modified autologous plasma exchanges on dynamics of hormone-metabolic homeostasis indices in patients with acute myocardial infarction].

Changes of biochemical indexes in the blood of 56 patients with acute myocardial infarction against the background of conventional and complex treatment using plasma exchange of extracorporeal-termally modified autoplasma have been analysed. The findings show that complex treatment of patients with AMI, using plasma exchange of extracorporal-thermally modified autoplasma, leads to much earlier decrease of KPK, LDH, LDH-1 enzyme activity in blood; it indicates the reduction of the period of myocardiocyte function restoration. The usage of plasma exchange of extracorporeal-thermally modified autoplasma in patients with acute myocardial infarction is accompanied by the absence of increase of glucose concentration in blood (owing to the normalization of insulin production), favourable influence on stress-reaction of biological systems of organism decrease of atherogenity index. Optimisation and efficiency of AMI therapy during treatment in the hospital is possible, with plasma exchange of extracorporeal-thermally modified autoplasma included in complex therapy.

Adult↗